Endothelial dysfunction (ED) has been shown to be of prognostic significance in predicting vascular events such as heart attack and stroke. It is the key event in the development of atherosclerosis and predates clinically evident vascular pathology by many years. ED can result from a variety of disease processes, such as hypertension, atherosclerosis, cardiovascular disease (heart disease and stroke), atrial fibrillation, congestive heart failure, peripheral vascular disease, septic shock, hypercholesterolemia, type I and II diabetes, erectile dysfunction, rheumatic arthritis, HIV, liver disease (cirrhosis, hepatitis B and C, non-alcoholic steatohepatitis, fatty liver disease), pre-eclampsia, heat stress, all forms of dementia and psychological illness, any and all illness related to localized or systemic inflammation, environmental factors such as smoking, ingestion of high glycemic index carbohydrates, sedentary lifestyle and obesity. ED is also associated with states of low grade, chronic inflammation with elevated C reactive protein which leads to atherosclerosis.
ED can be improved by risk factor modification: exercise, weight loss, cessation of smoking, the use of statin drugs, beta blockade, the treatment of hypertension and hypercholesterolemia, improved diet with reduction of trans fat intake, control of diabetes. Therefore, early detection of ED may allow not only early diagnosis and treatment of ED-related diseases, but also treatment of ED itself.
Plethysmography is a non-invasive technique for measuring the amount of blood flow present or passing through, an organ or other part of the body. Segmental volume plethysmography is performed by injecting a standard volume of air into a pneumatic cuff or cuffs placed at various levels along an extremity. Volume changes in the limb segment below the cuff are translated into pulsatile pressure that are detected by a transducer and then displayed as a pressure pulse contour. Segmental volume plethysmography has been commonly used to measure blood volume change. It may also be used to check for blood clots in the arms and legs.